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arXiv · 2406.19382

Contextuality of all optimal quantum cloning

Mina Doosti·Theodoros Yianni·Farid Shahandeh
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Abstract

Quantum contextuality is a key nonclassical feature underlying advantages in quantum computation and communication. We introduce a new method to study contextuality in quantum information-processing tasks and protocols, relying solely on observed information-processing statistics. Building on the framework of Shahandeh, Yianni and Doosti in arXiv:2512.10000 and employing rank separation techniques, we prove that contextuality is the necessary resource in both phase-covariant and universal optimal quantum cloning, thereby establishing its role as a fundamental source of nonclassicality in all known optimal cloning scenarios and resolving an open problem on the connection between cloning and contextuality. As a second application, we demonstrate the power of our method by providing a new, streamlined proof of contextuality in minimum-error quantum state discrimination.

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Mina Doosti, Theodoros Yianni, Farid Shahandeh. 2024-06-27. Contextuality of all optimal quantum cloning. https://arxiv.org/abs/2406.19382

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